Download Kitchen Microbiology

Kitchen Microbiology
Biotechnology – Use of Microbes
Your understanding of Microbes
What is a microbe?
Where do you find them?
Are they beneficial or harmful?
Microbes in the Kitchen



Microbes or MO (microorganisms) are a
part of our everyday life.
What did you eat yesterday? List them
in your notebook.
Let see if any of your food is made by
our tiny friends (MOs).
Commonly Known

Cheese/Butter –
Fermentation lowers the pH, thus helping
in the initial coagulation of the milk
protein, as well as giving characteristic
flavors. Some of the bacteria used in cheese
fermentation is found in smelly feet
(Streptococcus and Lactobacillus bacteria)

Bread -
provides a variety of
enzymes that enable carbohydrates to be
broken down producing sufficient carbon
dioxide to give bread its characteristic
texture. (Baker’s Yeast - Saccharomyces
cerevisiae)

Beer -Traditionally, the natural yeasts
on grape skins determine the quality of
wine produced. These natural yeasts,
especially Saccharomyces cerevisiae
(beer in Spanish is "cervesa") and
Saccharomyces ellipsoideus, ferment the
grapes to make wine.
Coffee/ Cocoa (chocolate)



Bacteria and yeast are
used to remove the
outer coats of coffee.
Erwinia dissolvens, leuconostoc, and
lactobacillus species, Saccharomyces
The microbes do not
affect the taste of
coffee but are
necessary to confer the
characteristic taste to
cocoa and chocolate.
Soy sauce/Vinegar

Soy sauce/Miso -
made from a mixture of soy beans
and rice fermented by a variety of
bacteria and fungi.
Lactobacillus delbrueckii, Aspergillus
oryzae, Aspergillus soyae, and
Saccharomyces rouxii

.
Vinegar -
Vinegar is made by two
distinct biological processes, both the result of
the action of harmless microorganisms (yeast
and “Acetobacter”) that turn sugars
(carbohydrates) into acetic acid.
The first process is called alcoholic fermentation and
occurs when yeasts change natural sugars to
alcohol under controlled conditions. In the
second process, a group of bacteria (called
“Acetobacter”) converts the alcohol portion to
acid.
Vitamins/MSG



Microbes may be used to elaborate
precursors in the making of Vitamins A,
C, and the B family. Using sugarbeet
molasses as a growth medium,
Pseudomonas denitrificans is made to
produce Vitamin B12. Members of the
genus Propionibacterium are also used to
make this vitamin. Although many
bacteria and fungi produce riboflavin
(B2), the fungus Ashbya gossypii
produces it in huge quantities.
MSG (monosodium glutamate) is
manufactured by Corynebacterium
glutamicum, a cousin of the diptheria
germ.
The fungus, Aspergillus niger, when
grown on sugarbeet molasses, produces
huge quantities of citric acid.
Amino Acids



Citric acid used to be extracted
primarily from lemons, but worldwide
demand for it forced the commercial
industry to seek other sources. The
fungus, Aspergillus niger, when grown on
sugarbeet molasses, produces huge
quantities of citric acid.
Glutamic acid requires
Corynebacterium glutamicum for its
formation. Biotin is a cofactor essential
for lipid synthesis in bacteria. By growing
C. glutamicum on limited amounts of
biotin, it causes the bacterial membrane
to leak sufficient quantities of glutamic
acid.
Lysine -- The bacterium, Brevibacterium
flavum is used in the industrial
biosynthesis of lysine. Mutants no longer
susceptible to feedback inhibition have
been isolated to be used industrially to
increase the yield of amino acids.
Meat Products

Meat products, like salami
and bologna sausages, require
some fermentation with
Pediuococcus cerevisiae,
Lactobacillus plantarum and
some members of the genus
Bacillus. Country cured hams
use fungi of the genus
Aspergillus and the genus
Penicillium in their fermentation
process. Izushi (sushi), a
Japanese delicacy made from a
mixture of fish, rice, and other
vegetables is produced by
fermentation with lactobacilli.
Pickled Food

Dill pickles are simply
fermented cucumbers.
Streptococci starts the
process of fermentation, but
as the pH level falls,
leuconostoc and pediococcus
species, as well as
Lactobacillus plantarum

continue the process.
Olives are edible only after
fermentation with
Lactobacillus plantarum and
Lactobacillus mesenteroides.
Homework


Find one thing at home that is made by
microorganism.
On a puzzle piece


Front: place a picture of the product, write
the name of the MO and the ingredient
produced by the MO.
Back: your name, period, and date